To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’. The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems. In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like. In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big Data processing technology through connection with a cloud server, has emerged. As technology elements, such as “sensing technology”, “wired/wireless communication and network infrastructure”, “service interface technology”, and “Security technology” have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth have been recently researched. Such an IoT environment may provide intelligent Internet technology services that create a new value to human life by collecting and analyzing data generated among connected things. IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing Information Technology (IT) and various industrial applications.
In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication may be implemented by beamforming, MIMO, and array antennas. Application of a cloud Radio Access Network (RAN) as the above-described Big Data processing technology may also be considered to be as an example of convergence between the 5G technology and the IoT technology.
Based on the rapid growth of wireless communication technologies, communication system technologies have also greatly evolved. Currently, the long term evolution (LTE) system is popularized as the fourth generation mobile communication technology. In the LTE system, a variety of technologies are used to address increasing traffic demands. One such technology is carrier aggregation (CA), which uses one or more secondary carriers as well as a main carrier rather than a single carrier for communication between a user equipment (UE) and an evolved node B (eNB). The use of secondary carriers can remarkably increase transmission capacity. In the LTE system, a cell using the main carrier is referred to as a primary cell (PCell), and a cell using the secondary carrier is referred to as a secondary cell (SCell). The eNB covers one PCell and up to four SCells according to LTE Release 11. However, the number of available SCells is expected to be increased. Such a cell may be used with a serving cell.
The LTE system has allowed a communication operator to use a licensed band frequency allocated by a government or the like. Recently, in order to meet increasing traffic demands, a scheme for using unlicensed bands allocated for wireless local area network (LAN), Bluetooth, etc. has been discussed in the art. This is referred to as licensed assisted access (LAA) technology. An example of one such unlicensed bands is 5 GHz band used for Wi-Fi.
The LAA technology may consider a scenario in which a PCell uses a licensed band frequency and an SCell uses an unlicensed band frequency.
However, since an unlicensed band has already been used by other type systems such as wireless LAN, Bluetooth, etc., an increased interference issue may occur in comparison with a licensed band. Further, for coexistence with other systems, it is not easy to continuously use an unlicensed band.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.